Combustion chamber arrangement



Oct. '27, 1964 T. SEIFFERLEIN COMBUSTION CHAMBER ARRANGEMENT Filed July 20, 1960 INVENTOR THEO SEIFFERLEIN BY Aa, V f

ATTORNEYS 3,154,516 COMBUSTION CHAMBER ARRANGEMENT Theo Seiflerlein, Stuttgart-Bad Cannstatt, Germany, as-

signor to Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturlrheim, Germany Filed July 20, 196i), Ser. No. 44,087 (Ilaims priority, application Germany July 28, 1959 4 Claims. (61. fill-69.72)

The present invention relates to an annularly-shaped flame holder arrangement for the combustion chambers of gas turbines, jet propulsion units and the like, which is disposed concentrically to the axis of the engine.

The flame holder according to the present invention comprises a center ring which, when viewed in the direction of air flow, is convex and on which are arranged the fuel injection nozzles, and inner and outer air guiding surfaces also of annular configuration which, in cooperation with the lateral surfaces of the center ring, guide the air past the center ring. As a result thereof, there is imparted to the air at the end of the lateral surfaces of the center ring as well as at the end of the inner and outer air guiding surfaces a vorticity which leads to the reversal of the direction of flow thereof necessary for the holding or maintaining of the flame and which extends over a large radial width or area.

It is further proposed in accordance with the present invention to dispose the ends of the inner and outer air guiding surfaces in a staggered manner, as viewed in the direction of air flow, with respect to the ends of the lateral surfaces of the center ring. Owing to such a staggered arrangement, the flame-holding or flame-maintaining vortices are off-set against each other.

According to another embodiment of the present invention, the flame holder may also be made in such a manner that web portions are provided at regular intervals between the lateral surfaces of the center ring and the inner and outer air guiding surfaces so that the air is guided past the center ring through a number of individual channels. In this arrangement, the edges of the web portions act as additional discontinuity edges for the vortex formation. Furthermore, a layer-like non-uniformity or stratified irregularity is formed, as viewed in the circumferential direction, which has a favorable effect particularly with respect to the subsequent admixture of the secondary air in that this secondary air necessitates less excess pressure with equally good intermixture.

When the web portions are provided with a cross section whichwhen viewed in the direction of air floW--is convex, the air is guided past the webs in a relatively favorable manner as regards the aerodynamics thereof. If these V-shaped web portions are utilized in an embodiment in which the inner and outer air guiding surfaces are extended further-as viewed in the direction of air flowthan the lateral surfaces of the center ring, then groove-like recesses will be formed between the toothed individual channels through which fuel jets from the injection nozzles may pass into the outer combustion region to thus secure also an effective combustion therein.

Accordingly, it is an object of the present invention to provide a flame-holder device which is extremely effective for its intended purposes and achieves such high degree of efficiency by relatively simple means.

It is another object of the present invention to provide a flame-holder structure for the combustion chambers of gas turbines, jet propulsion units or the like which effectively maintains the flame in a predetermined area within the proximity of the injection nozzles.

Another object of the present invention is the provision, for gas turbines, jet propulsion units or the like, of a flameholder arrangement which effectively maintains the flame nited States Patent "ice 3,154,515 Patented Oct. 27, 1964 in the combustion chambers essentially within a predetermined area to thereby prevent flame-out of the engine.

It is a still further object of the present invention to provide a flame-holder arrangement for the combustion chambers of gas turbines, jet propulsion units or the like in which the vortex formation necessary for the flameholding function is effectively enhanced by the physical lay-out of the air guiding surfaces in such a way as to improve the combustion process by enabling intimate mixing of the fuel and primary air, favorable admixing of the secondary air, and full utilization of the entire combustion area together with favorable aerodynamic flow conditions for the various air streams.

These and other objects, features and advantages of the present invention will become more obvious from the following description, when taken in connection with the accompanying drawing which shows, for purposes of illustration only, two embodiments in accordance with the present invention and wherein:

FIGURE 1 is a partial longitudinal, cross-sectional view through a first embodiment of a combustion chamber in accordance with the present invention provided with annularly-shaped air passage channels on the flame holder;

FIGURE 2 is a partial cross-sectional view taken along line IIII of FIGURE 1 of the combustion chamber having annularly-shaped air passage channels on the flame holder;

FIGURE 3 is a partial end view of a flame holder provided with individual channels as seen in a direction opposite the direction of air flow, and

FIGURES 4 and 5 are cross-sectional views, on an enlarged scale, through the flame holder of FIGURE 3 taken along lines IV--IV and V-V thereof.

Referring now to the drawing, wherein like reference numerals are used throughout the various views to designate like parts, and more particularly to the embodiment of FIGURES 1 and 2, reference numeral 10 designates therein the shaft of the gas turbine. The annular combustion chamber is delimited or defined by two annular walls 11 and 12. Two annular channels 38, 39 for the secondary air which are delimited by walls 11 and 13, and 14 and 12, respectively, adjoin the combustion chamber walls 11 and 12. The flame holder in accordance with the present invention essentially consists of a center ring 15 which is convex as viewed in the direction of air flow and on which are provided the injection nozzles 16, and of an inner and an outer annular air guiding surface 17 and 18, respectively. The primary air flow is designated by arrows 40. The flame-holding or maintaining vortices 19-22 are formed adjacent the discontinuity edges of the wall surfaces 15, 17, 18 over the entire radial area of the combustion chamber. Center ring 15 has a concave surface surrounding the injection nozzles 16 effectively forming an underpressure zone or dead air space 46. An outer annular dead air space 44 is formed between annular wall 11 and the outer annular air-guiding surface 18. Similarly, a dead air space 42 is formed between annular wall 12 and the inner air-guiding surface 17. The sudden termination of the edges of wall surfaces 15, 17 and 18, and the dead air spaces 46, 42, and 44 on one side of each of the wall surfaces effectively form the vortices 19-22. The secondary air is admixed to the combustion gases at 23 and 24. The web portions supporting the individual annular elements of the flame holder which may be of any suitable known construction have not been shown in FIGURES 1 and 2 for reasons of clarity.

In the embodiment according to FIGURES 3 to 5, the air is guided into the individual channels 25 and 26 by means of the flame holder. Web portions 27 and 28 having a V-shaped or saw tooth cross section are provided between the individual channels. The individual channels 25 and 26 are arranged in respective arcuate rows which diverge with respect to each other. Arrows 29 and 30 (FIGURES 4 and 5) show how fuel may be injected from the injection nozzles through the V of the web portions into the outer regions of the combustion chamber. The cross sections of web portions 27 and 28 are such that between adjacent individual channels 25 or 26, there are formed essentially radially extending under-pressure zones or dead air spaces. The nozzles are thereby inserted into the nozzle holders 31 provided between channels 25 and 26. The right hand ends of channels 25 and 26 seen in FIGURE 4 are each provided in different transverse planes through the turbine. As shown therein, the outer channels 25 are outwardly inclined with respect to turbine shaft 12 by a smaller angle than the inner channels 26 are inwardly inclined with respect to shaft 10. This results in the direction of the combustion gases, as seen as a whole, being inwardly orientated with a temperature gradient in the direction of flow toward shaft 10.

While I have shown and described herein two embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit and scope of the present invention, and I, therefore, do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. An essentially annular flame-holder device for the combustion chambers of gas turbines, jet propulsion units and the like, said flame-holder device being essentially concentric with respect to the longitudinal axis of the combustion chamber, comprising an annular center ring member provided with fuel injection means, said center ring member being essentially convexly shaped in the direction of flow of the air, and inner and outer annular air guiding surface means cooperating with the lateral surfaces of said center ring member to guide the air past said center ring member, said inner and outer annular air guiding surface means forming pluralities of individ- .1

ual inner and outer air channels, respectively, said air channels having discharge apertures in planes inclined with respect to a vertical plane perpendicular to said longitudinal axis of the combustion chamber.

2. An essentially annular flame holder device for the combustion chambers of gas turbines and the like, said flame holder device being essentially concentrically positioned with respect to the longitudinal axis of the combustion chamber, an annular center ring member provided with a plurality of spaced fuel injection means, said center ring member having a concave surface effectively forming a dead air space around said fuel injection means, inner and outer annular air-guiding surfaces cooperating with the lateral surfaces of said center ring member forming an air passage to guide combustion air past said center ring member, inner and outer wall means cooperating with said inner and outer annular air-guiding surfaces respectively to form inner and outer essentially annular dead air spaces, and vortex-forming means including said dead air spaces and web portions for effectively producing flame holding vortices in the combustion air, said web portion being provided between said inner and outer annular air-guiding surfaces and the lateral surfaces of said center ring member to form a number of individual channels through which combustion air is glided, said web portions being contoured to provide an essentially radially extending dead air space between each pair of circumferentially adjacent individual channels.

3. An essentially annular flame holder device for the combustion chambers of gas turbines and the like, said flame holder device being essentially concentrically positioned with respect to the longitudinal axis of the combustion chamber, an annular center ring member provided with a plurality-of spaced fuel injection means, said center ring member having a concave surface effectively forming a dead air space around said fuel injection means, inner and outer annular airguiding surfaces cooperating with the lateral surfaces of said'center ring member forming an air passage to guide combustion air past said center ring member, inner and outer wall means cooperating with said inner and outer annular air-guiding surfaces respectively to form inner and outer essentially annular dead air spaces, and vortex-forming means including said dead air spaces and web portions of essentially saw tooth cross section for effectively producing flame holding vortices in the combustion air, said web portions being provided between said inner and outer annular air-guiding surfaces and the lateral surfaces of said center ring member to form a plurality of individual inner and outer air channels at the downstream ends of said web portions, said saw tooth cross section of said web portions forming essentially radially extending dead air spaces between adjacent ones of said air channels, said inner channels being inclined towards the longitudinal axis of the combustion chamber and said outer channels being inclined away from the longitudinal axis of the combustion chamber forming vortices effective to entrain fuel from said fuel injection means inwardly and outwardly respectively.

4. An essentially annular flame holder device for a combustion chamber having a longitudinal axis, comprising an annular center ring member positioned around said longitudinal axis and including a plurality of circumferentially spaced fuel injection nozzles, inner and outer annular air-guiding surfaces around said center ring member, and web means between said inner air-guiding surface and said center ring member and between said outer annular air-guiding surface and said center ring member forming inner and outer rows of individual air channels to guide combustion air past said center ring member, the inner individual air channels being inclined inwardly with respect to said longitudinal axis, the outer individual air channels being inclined outwardly with respect to said longitudinal axis with a smaller angle than the inward inclination of the inner individual air channels, said center ring member being contoured to provide an essentially dead air space around said fuel injection nozzles, and wall means cooperating with said inner and outer annular air-guiding surfaces effective to form inner and outer dead air spaces, said web means being contoured to provide an essentially radially extending dead air space between respective ones of said inner individual air channels and to provide an essentially radially extending dead air space between respective ones of said outer individual air channels, and means including said dead air spaces and said air channels for effectively maintaining the flame essentially within the region of the combustion chamber adjacent the fuel injection nozzles.

References Cited in the file of this patent UNITED STATES PATENTS 2,689,457 Kruppe Sept. 21, 1954 2,780,060 Griffith Feb. 5, 1957 2,914,912 Woll Dec. 1, 1959 2,934,895 Gregory et a1. May 3, 1960 2,948,117 Nerad Aug. 9, 1960 2,959,006 Ferrie Nov. 8, 1960 3,026,675 Vesper et al Mar. 27, 1962 FOREIGN PATENTS 744,659 Great Britain Feb. 8, 1956 780,493 Great Britain Aug. 7, 1957 

1. AN ESSENTIALLY ANNULAR FLAME-HOLDER DEVICE FOR THE COMBUSTION CHAMBERS OF GAS TURBINES, JET PROPULSION UNITS AND THE LIKE, SAID FLAME-HOLDER DEVICE BEING ESSENTIALLY CONCENTRIC WITH RESPECT TO THE LONGITUDINAL AXIS OF THE COMBUSTION CHAMBER, COMPRISING AN ANNULAR CENTER RING MEMBER PROVIDED WITH FUEL INJECTION MEANS, SAID CENTER RING MEMBER BEING ESSENTIALLY CONVEXLY SHAPED IN THE DIRECTION OF FLOW OF THE AIR, AND INNE R AND OUTER ANNULAR AIR GUIDING SURFACE MEANS COOPERATING WITH THE LATERAL SURFACES OF SAID CENTER RING MEMBER TO GUIDE THE AIR PAST SAID CENTER RING MEMBER, SAID INNER AND OUTER ANNULAR AIR GUIDING SURFACE MEANS FORMING PLURALITIES OF INDIVIDUAL INNER AND OUTER AIR CHANNELS, RESPECTIVELY, SAID AIR CHANNELS HAVING A DISCHARGE APERTURES IN PLANES INCLINED WITH RESPECT TO A VERTICAL PLANE PERPENDICULAR TO SAID LONGITUDINAL AXIS OF THE COMBUSTION CHAMBER. 